--- a/scripts/plot/module.mk	Wed Jun 01 08:53:08 2011 -0700
+++ b/scripts/plot/module.mk	Wed Jun 01 23:58:35 2011 +0200
@@ -141,6 +141,7 @@
   plot/print.m \
   plot/quiver.m \
   plot/quiver3.m \
+  plot/rectangle.m \
   plot/refresh.m \
   plot/refreshdata.m \
   plot/ribbon.m \

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/scripts/plot/rectangle.m	Wed Jun 01 23:58:35 2011 +0200
@@ -0,0 +1,220 @@
+## Copyright (C) 2011 David Bateman
+##
+## This file is part of Octave.
+##
+## Octave is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or (at
+## your option) any later version.
+##
+## Octave is distributed in the hope that it will be useful, but
+## WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+## General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with Octave; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {} rectangle ()
+## @deftypefnx {Function File} {} rectangle (@dots{}, "Position", @var{pos})
+## @deftypefnx {Function File} {} rectangle (@dots{}, "Curvature", @var{curv})
+## @deftypefnx {Function File} {} rectangle (@dots{}, "EdgeColor", @var{ec})
+## @deftypefnx {Function File} {} rectangle (@dots{}, "FaceColor", @var{fc})
+## @deftypefnx {Function File} {@var{h} =} rectangle (@dots{})
+##
+## Draw rectangular patch defined by @var{pos} and @var{curv}. The variable
+## @code{@var{pos}(1 : 2)} defines the lower left-hand corner of the patch
+## and @code{@var{pos}(3 : 4)} its width and height. By default the value of
+## @var{pos} is @var{[0, 0, 1, 1]}.
+##
+## The variable @var{curv} defines the curvature of the sides of the rectangle
+## and it can be a scalar or two-element vector with values between 0 and 1.
+## A value of 0 represents no curvature of the side, where as a value of 1
+## means that the rectangular side is entirely curved into an arc of a circle.
+## If curvature is a two-element vector, then the first element is the 
+## curvature along the x-axis of the patch and the second along y-axis.
+##
+## If @var{curv} is a scalar, it represents the curvature of the shorter of the
+## two sides of the rectangle and the curvature of the other side is defined
+## by
+##
+## @example
+## min (pos (1: 2)) / max (pos (1:2)) * curv
+## @end example
+##
+## Other properties are passed to the underlying patch command. If called 
+## with an output argument, @code{rectangle} returns the handle to the 
+## rectangle.
+## @end deftypefn
+## @seealso{patch}
+
+function h = rectangle (varargin)
+
+  [hax, varargin] = __plt_get_axis_arg__ ("rectangle", varargin{:});
+
+  tmp =  __rectangle__ (hax, varargin{:});
+
+  if (nargout > 0)
+    h = tmp;
+  endif
+endfunction
+
+function hg = __rectangle__ (hax, varargin)
+
+  iarg = 1;
+  pos = [0, 0, 1, 1];
+  curv2 = [0, 0];
+  ec = [0, 0, 0];
+  fc = "none";
+
+  while (iarg < length (varargin))
+    arg = varargin{iarg};
+    if (ischar(arg))
+      if (strcmpi (arg, "position"))
+        pos = varargin{iarg+1};
+        varargin(iarg:iarg+1) = [];
+        if (!isvector (pos) || numel (pos) != 4)
+          error ("rectangle: position must be a 4 element vector");
+        endif
+      elseif (strcmpi (arg, "curvature"))
+        curv2 = varargin{iarg+1};
+        varargin(iarg:iarg+1) = [];
+        if (!isnumeric (curv2) || (numel (curv2) != 1 && numel (curv2) != 2))
+          error ("rectangle: curvature must be a 2 element vector or a scalar");
+        endif
+        if (any (curv2 < 0) || any (curv2 > 1))
+          error ("rectangle: curvature values must be between 0 and 1");
+        endif
+      elseif (strcmpi (arg, "edgecolor"))
+        ec = varargin{iarg+1};
+        varargin(iarg:iarg+1) = [];
+      elseif (strcmpi (arg, "facecolor"))
+        fc = varargin{iarg+1};
+        varargin(iarg:iarg+1) = [];
+      else
+        iarg ++;
+      endif
+    else
+      iarg ++;
+    endif
+  endwhile
+
+  if (numel (curv2) == 1)
+    [a, ai] = min (pos (3 : 4));
+    [b, bi] = max (pos (3 : 4));
+    if (ai < bi)
+      curv = [curv2, curv2 .* a ./ b];
+    else
+      curv = [curv2 .* a ./ b, curv2];
+    endif
+  else
+    curv = curv2;
+  endif
+
+  if (all (curv) < 0.01)
+    ## Special case : no curvature
+    x = [pos(1), pos(1) + pos(3), pos(1) + pos(3), pos(1), pos(1)];
+    y = [pos(2), pos(2), pos(2) + pos(4), pos(2) + pos(4), pos(2)];
+  else
+    p = pi / 2 * [0 : 15] / 15;
+    c = curv .* pos(3 : 4) / 2;
+    cx = c(1) * sin (p) - c(1);
+    cy = c(2) * cos (p) - c(2);
+    x = [pos(1) - fliplr(cx), pos(1) + pos(3) + cx, ...
+         pos(1) + pos(3) + fliplr(cx), pos(1) - cx, pos(1)];
+    y = [pos(2) - fliplr(cy), pos(2) - cy, pos(2) + pos(4) + fliplr(cy), ...
+         pos(2) + pos(4) + cy, pos(2) + c(2)];
+  endif
+
+  hg = hggroup ();
+
+  h = patch ("xdata", x(:), "ydata", y(:), "facecolor", fc, "edgecolor", ec, ...
+             "parent", hg, varargin{:});
+
+  addproperty ("curvature", hg, "data", curv2);
+  addproperty ("position",  hg, "data", pos);
+  addproperty ("edgecolor", hg, "patchedgecolor", get (h, "edgecolor"));
+  addproperty ("linewidth", hg, "patchlinewidth", get (h, "linewidth"));
+  addproperty ("linestyle", hg, "patchlinestyle", get (h, "linestyle"));
+  addproperty ("facecolor", hg, "patchfacecolor", get (h, "facecolor"));
+
+  addlistener (hg, "curvature", @update_data);
+  addlistener (hg, "position",  @update_data);
+  addlistener (hg, "edgecolor", @update_props);
+  addlistener (hg, "linewidth", @update_props);
+  addlistener (hg, "linestyle", @update_props);
+  addlistener (hg, "facecolor", @update_props);
+endfunction
+
+function update_data (h, d)
+  persistent recursion = false;
+
+  ## Don't allow recursion
+  if (!recursion)
+    unwind_protect
+      recursion = true;
+
+      kids = get (h, "children");
+      pos = get (h, "position");
+      curv2 = get (h, "curvature");
+
+      if (numel (curv2) == 1)
+        [a, ai] = min (pos (3 : 4));
+        [b, bi] = max (pos (3 : 4));
+        if (ai < bi)
+          curv = [curv2, curv2 .* a ./ b];
+        else
+          curv = [curv2 .* a ./ b, curv2];
+        endif
+      else
+        curv = curv2;
+      endif
+
+      if (all (curv) < 0.01)
+        ## Special case : no curvature
+        x = [pos(1), pos(1) + pos(3), pos(1) + pos(3), pos(1), pos(1)];
+        y = [pos(2), pos(2), pos(2) + pos(4), pos(2) + pos(4), pos(2)];
+      else
+        p = pi / 2 * [0 : 15] / 15;
+        c = curv .* pos(3 : 4) / 2;
+        cx = c(1) * sin (p) - c(1);
+        cy = c(2) * cos (p) - c(2);
+        x = [pos(1) - fliplr(cx), pos(1) + pos(3) + cx, ...
+             pos(1) + pos(3) + fliplr(cx), pos(1) - cx, pos(1)];
+        y = [pos(2) - fliplr(cy), pos(2) - cy, pos(2) + pos(4) + fliplr(cy), ...
+             pos(2) + pos(4) + cy, pos(2) + c(2)];
+      endif
+
+      set (kids, "xdata", x, "ydata", y);
+    unwind_protect_cleanup
+      recursion = false;
+    end_unwind_protect
+  endif
+endfunction
+
+function update_props (h, d)
+  kids = get (h, "children");
+  set (kids, "edgecolor", get (h, "edgecolor"),
+       "linewidth", get (h, "linewidth"),
+       "linestyle", get (h, "linestyle"),
+       "facecolor", get (h, "facecolor"));
+endfunction
+
+%!demo
+%! close all
+%! axis equal
+%! rectangle ("Position", [0.05, 0.05, 0.9, 0.9], "Curvature", [0.5, 0.5]);
+
+%!demo
+%! close all
+%! axis equal
+%! rectangle ("Position", [0.05, 0.05, 0.9, 0.4], "Curvature", 1.0);
+
+%!demo
+%! close all
+%! axis equal
+%! h = rectangle ("Position", [0.05, 0.05, 0.9, 0.4], "Curvature",  1.0);
+%! set (h, "FaceColor", [0, 1, 0]);
+